
//写cookies 
function setCookie(name,value) { 
    var days = 1; 
    var exp = new Date(); 
    exp.setTime(exp.getTime() + days*24*60*60*1000); 
    document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString()+";path=/";  
} 

//读取cookies 
function readCookie(name) { 
    var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");
    if(arr=document.cookie.match(reg)){
        return unescape(arr[2]); 
    }else{
        return null;
    }
        
} 

//删除cookies 
function delCookie(name) { 
    var cval=readCookie(name); 
    if(cval!=null){
        document.cookie= name + "="+cval+";expires="+(new Date(0)).toGMTString()+";path=/";   
    }
}